[clang] [clang] Implement gcc_struct attribute on Itanium targets (PR #71148)

[Eli Friedman via cfe-commits]

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@@ -997,6 +997,9 @@ def warn_npot_ms_struct : Warning<
   "data types with sizes that aren't a power of two">,
   DefaultError, InGroup<IncompatibleMSStruct>;
 
+def err_itanium_layout_unimplemented : Error<
+  "Itanium-compatible layout for the Microsoft C++ ABI is not yet supported">;
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efriedma-quic wrote:

Missing testcase for this diagnostic.

https://github.com/llvm/llvm-project/pull/71148